Arari River

The Arari River (Portuguese: Rio Arari) is a river of Marajó, which itself is an island in the Amazon Delta. It is located in the state Pará in northern Brazil. This river begins its journey in the south of Lake Arari and flows through swampy areas called mondongos, which are often flooded during the wet season.

As the river continues, it becomes more straight after passing Cachoeira do Arari. The water here looks dark and muddy because it is covered with aninga plants. Near where it meets Marajó Bay, the river widens and its banks become rocky. Many lakes line the river, especially in the middle and lower parts, with some being around 10 km long and 0.6 km wide.

The Arari River is connected to the Marajó-Açu River through a stream called Furo das Laranjeiras. Depending on the water level in Marajó Bay, the river can sometimes flow in the opposite direction for part of its course. This change affects many things like oxygen levels, temperature, acidity, turbidity, water quality, and the Trophic State Index.

People use the land along the river for large water buffalo farms, which add nutrients to the water. Small farmers use the river for everyday needs, growing crops, and fishing. Fish from the Arari River, like Tamoatá fish, make up 6% of sales in the Ver-o-Peso market in Belém.